Slotted overwrapped tray

ABSTRACT

A tray assembly for a perishable foodstuff has a tray body with at least one overwrap layer. The body in use has an inner area for the foodstuff. The body has side portions separating an upper end and a lower end. The upper end provides a lip boundary portion and the lower end provides a base portion. The overwrap layer comprises a plastics film material. The plastics film material covers and spans the lip boundary portion to provide a first enclosed space for the perishable foodstuff and a second enclosed space outside the body. The body has at least one slot in the lip boundary portion to provide gas communication between the first enclosed space and the second enclosed space. The plastics material of the second enclosed space has side perforations to facilitate gas exchange between the second enclosed space and the area outside the tray assembly.

FIELD OF THE INVENTION

[0001] This invention relates to an overwrapped tray assembly The invention is directed particularly, but not necessarily solely toward a tray assembly for perishable foodstuffs.

BACKGROUND OF THE INVENTION

[0002] Fresh meat foodstuffs are processed into various cuts at the meat processing plant where they are then packaged prior to sending to the retail market. The packaging step includes placing the cuts of meat within a tray which is then over wrapped with a non-barrier plastic film. The over wrapped trays are then placed within a barrier bag.

[0003] It is known in the art to package fresh meat in a modified atmosphere environment whereby the packaging is flushed with a preservation-enhancing gas mixture such as carbon-dioxide. In U.S. Pat. Nos. 5,667,827 and 5,711,978 both issued to Breen et al., disclose a process of packaging fresh meat and a fresh meat packaging which provide an inexpensive, retail case-ready packaging for perishable foodstuffs, such as fresh meat. The prolonged shelf life for the packaged meat foodstuffs ranges from about 40 to 90 days after which the meat still blooms up to a desired fiery red colour upon exposure of the packaged meat foodstuff to oxygen. The invention described in these two U.S. patents relates to a tray being overwrapped to provide a first and a second enclosed region, a first perforation means disposed along upper portions of said tray allows for gas exchange between said first and second enclosed regions without clogging due to run off juices from the meat or due to shifting of the meat within the tray; and a second perforation means disposed in the plastic wrapping material to permit gas exchange between said second enclosed region and a region outside of the overwrapped tray.

[0004] It has been suprisingly discovered that a single slot in the lip boundary portion of an overwrapped tray assembly improves evacuation of oxygen from the tray.

OBJECT OF THE INVENTION

[0005] It is the object of the present invention to provide an improved overwrapped tray assembly which will obviate or minimise the known problems of packaging perishable foodstuffs in a simple yet effective manner or which will at least provide the public with a useful choice.

STATEMENT OF INVENTION

[0006] A first aspect of the invention provides for a tray assembly for a perishable foodstuff having a tray body, the body in use having an inner area for the foodstuff, and having side portions separating an upper end and a lower end, the upper end providing a lip boundary portion and the lower end providing a base portion, and at least one overwrap layer comprising a plastics film material, the plastics film material covering and spanning the lip boundary portion to provide a first enclosed space for the perishable foodstuff and a second enclosed space outside the body, the body having at least one slot in the lip boundary portion to provide gas commnunication between the first enclosed space and the second enclosed space and wherein the plastics material of the second enclosed space has side perforations to facilitate gas exchange between the second enclosed space and the area outside the tray assembly. Preferably the slot is sized so as to not be blocked by the plastics film material when venting in a vacuum apparatus.

[0007] Preferably the slot has a cross-sectional area of at least 5 square millimetres so as not to be blocked with the foodstuff exudate.

[0008] Alternatively there are a plurality of slots.

[0009] Alternatively the slot extends into the side portions.

[0010] Alternatively the tray body has two layers.

[0011] Preferably at least one tray body layer comprises a substantially solid plastics material.

[0012] Alternatively at least one tray body layer comprises a substantially closed cell foam material.

[0013] Alternatively at least one tray body layer comprises a substantially open cell foam material.

[0014] To those skilled in the art to which the invention relates, many changes in construction or embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The following description of the preferred embodiment is given by way of example only and is not intended to be in any sense limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 shows a perspective view of the tray assembly of the preferred embodiment of the invention.

[0016]FIG. 2 shows a plan view of the tray shown in FIG. 1.

[0017]FIG. 3 is a cross sectional view of part of the tray assembly shown in FIG. 1 showing the enclosed spaces.

DETAILED DESCRIPTION OF THE DRAWINGS

[0018] As shown in FIG. 1 the tray assembly 1 has a body 2 and an overwrap material 3. The overwrap material 3 is a plastics film material. The body 2 has an upper end and a lower end. A lip boundary portion 4 being at the upper end and a base portion 6 being at the lower end, are separated by side portions 5. The body 2 has a slot 7 in the lip portion 4, to create a gas communication. The tray body 2 has an inner area in which the perishable foodstuff sits. The overwrap material 3 covers the inner area and spans the lip boundary portion 4 to create a first enclosed space 10. The overwrap material 3 covers the lip boundary portion 4 and as the term ‘overwrap’ indicates, extends past the lip boundary portion 4 to seal S against the outer side of the base portion 6. This extension with the base portion 6 creates a second enclosed space 11. The slot 7 creates a gas communication means between the enclosed spaces 10 and 11 which improves the efficiency of the evacuation process to remove air. To further facilitate evacuation of air during the evacuation process, the overwrap material 3 has side perforations 14. The side perforations 14 enable evacuation of the second enclosed space 11 to the outside of the assembly.

[0019] The overwrap material 3 can include any plastics film material suitable to enable the first step of air or oxygen evacuation to occur when at least one overwrapped tray assembly is placed in an outer oxygen barrier bag which is then flushed with a preservation enhancing gas such as carbon dioxide. After the outer barrier bag has been evacuated and flushed it is then sealed for transportation. The overwrap material 3 can be clear or not clear. If a clear overwrap material 3 is used, this can enable customer viewing. However the degree of clearness of the overwrap material is not important, as in some uses, the overwrap material 3 can be covered up with advertizing or messages. The overwrap material should be inexpensive and must be flexible and yet strong enough to cover the tray inner area and form the first enclosed space 10 and the second enclosed space 11 and work with any evacuation process that is utilized. FIG. 2 shows the slot 7 with respect to the side portions 5 of the body 2. As shown in FIG. 3 the tray assembly 1 shows the enclosed space 10 with the inner area for the perishable foodstuff, and the enclosed space 11.

[0020] The overwrap material can be any thin plastics material. Alternatively, the overwrap material can be any thin plastics material that can be sealed to itself or to the tray body 2, or can be sealed to both itself and the tray body, and can be evacuated. For example the material can be heat sealed to the tray body base portion i.e. the overwrap material 3 is gathered underneath the tray body and welded with the tray body by partial welding (e.g. by hot plates) or hermetically sealed. Alternatively the overwrap material 3 can be sealed to the outer side portions of the tray body. The overwrap material 3 could be in the form of a thin plastics bag that is able to be heat shrunk or stretch wrapped around the tray body and then sealed.

[0021] The overwrap material 3 when in place over the body 2 has a top portion 12, side portions 13 and a bottom portion 14. In another alternative the second enclosed space can also extend downwards and underneath the base portion 6.

[0022] Alternatively or in combination with the side perforations 15, there can be further perforations in the overwrap material 3 bordering enclosed space 10 i.e. the top portion 12 These further perforations are not shown in the drawings. The slot 7 should not be too large so that the selected material used for the overwrap material 3 sags under its own weight or during an evacuation process, across the slot 7 and thereby blocks the slot 7. The overwrap material 3 can be made up of a film or a blend of materials and or a series of layers or laminations.

[0023] The slot 7 preferably has a cross-sectional area of at least substantially 5 square millimetres so that run off juices or exudate from the perishable foodstuff should not block the slot 7. There can be more than one slot 7 depending on the physical requirements of the preservation process e.g. evacuation pressure required coupled with the strength of the materials used. The slot 7 can be a recess or a channel and can be of any depth suitable or adapted such that total evacuation for the assembly can occur during the process of preserving the perishable foodstuff. The slot or slots can extend into the side portions 5. The slot(s) must be large enough to allow gas communication during evacuation to remove oxygen and large enough so as not to be blocked with the exudate. If the slot is too small it could be blocked by the foodstuff exudate. It is preferred that the perishable foodstuff is fresh meat, though other foodstuffs that need preserving using the outer oxygen barrier bag can also be stored.

[0024] Preferably the tray body comprises a substantially solid plastics material. The tray body 2 can comprise an open or closed cell material or a combination of open and closed cell materials. Blends or laminated or combined layers of any of these material types can also be used. The material selected must be strong enough to withstand the vacuum packaging process, transportation, storage and display and yet be cost effective.

[0025] Throughout the description and claims of this specification the word “comprise” and variations of that word, such as “comprising”, are not intended to exclude other additives, components, integers or steps.

ADVANTAGES

[0026] The tray assembly has the following advantages:

[0027] 1. Easy to manufacture.

[0028] 2. Inexpensive to produce.

[0029] 3. Tray has a slot to improve the evacuation of the tray assembly. 

What is claimed is:
 1. A tray assembly for a perishable foodstuff having a tray body, the body in use having an inner area for the foodstuff, and having side portions separating an upper end and a lower end, the upper end providing a lip boundary portion and the lower end providing a base portion, and at least one overwrap layer comprising a plastics film material, the plastics film material covering and spanning the lip boundary portion to provide a first enclosed space for the perishable foodstuff and a second enclosed space outside the body, the body having at least one slot in the lip boundary portion to provide gas communication between the first enclosed space and the second enclosed space and wherein the plastics material of the second enclosed space has side perforations to facilitate gas exchange between the second enclosed space and the area outside the tray assembly.
 2. The tray assembly as claimed in claim 1 wherein the slot is sized so as not to be blocked by the plastics film material when venting in a vacuum apparatus.
 3. The tray assembly as claimed in claim 2 wherein the slot has a cross sectional area of at least 5 square millimetres so as to not to be blocked with foodstuff exudate.
 4. The tray assembly as claimed in claim 3 wherein there are a plurality of slots.
 5. The tray assembly as claimed in claim 4 wherein the slot extends into the side portions of the body.
 6. The tray as claimed in claim 5 wherein the tray body has two layers.
 7. The tray assembly as claimed in claim 6 wherein at least one layer comprises a substantially solid plastics material.
 8. The tray assembly as claimed in claim 6 wherein at least one layer comprises a substantially closed cell foam material.
 9. The tray assembly as claimed in claim 6 wherein at least one layer comprises a substantially open cell foam material. 